Electrostatic discharge (ESD) protection design is a major factor with respect to the reliability of integrated circuits. Generally, ESD is the transfer of an electrostatic charge between bodies at different electrostatic potentials or voltages, caused by direct contact or induced by an electrostatic field. The device size and the thickness of the oxide and of the insulating layers of transistors of integrated circuits are being continually reduced to improve the operating speed of the transistors and integration density of the integrated circuits. These highly scaled-down devices, however, have been found to be increasingly vulnerable to ESD. Therefore, ESD protection circuits have been added to the integrated circuits to protect the integrated circuits against ESD damage. ESD protection circuits may be implemented around the input, output and supply pads of the integrated circuits to bypass ESD current away from the internal devices of the integrated circuits.